The good old days of the German sport sedan were much simpler times. Your carmaker of choice – be it Audi, BMW or Mercedes – would bolt together a supremely competent family sedan that blended high-class comfort and luxury with the abili...
The good old days of the German sport sedan were much simpler times. Your carmaker of choice – be it Audi, BMW or Mercedes – would bolt together a supremely competent family sedan that blended high-class comfort and luxury with the ability to cruise leisurely at triple-digit speeds should the need arise. Then, for those who demanded more performance, their motorsport departments would simply massage the power, the chassis and the cosmetics before appending special letters to the badge – S, M or AMG, respectively. Voila, your uber-sedan is ready!
But that was all before the turbo revolution of the last few years. Where we once were given the choice of either standard or hot-rod variants, today there exists a broad spectrum of performance options thanks to the nearly infinite tuning possibilities of the modern turbo engine.
Within BMW alone, most models offer a Sport package, an M Sport package and a full-on M model. Mercedes-Benz has Sport and AMG packages as well as proper AMG models, with optional enhanced performance packages for those, even. Audi offers a similar progression, starting with its S-Line and moving up to S models before reaching the pinnacle RS designation.
With so many choices, striking the right balance between functionality and performance is harder than ever. Enter the Audi S6, freshly updated for 2013 with a fresh makeover and a new twin-turbo V8 feeding its legendary quattro drivetrain. While it represents the top of the mid-size A6 lineup in America (we don’t get the true range-topper RS6, which is built exclusively as a wagon), it actually ends up a bit of an in-betweener in the market. Its most direct BMW competitor, for instance isn’t the M5 but rather the 550i with the M Sport option.
Like the last-gen BMW M5, Audi’s previous S6 was powered by a high-revving V10, in this case a 5.2-liter that shared its basic architecture with the engine in Lamborghini’s Gallardo. Large displacement and high revs make for a thirsty beast though, and in the face of stricter emissions and fuel economy standards, Audi chose a more efficient path for 2013 and beyond. The new formula, as adhered to by BMW and Mercedes as well, involves a smaller direct-injected V8 for everyday efficiency, boosted by a pair of turbos when additional performance is required.
The 4.0-liter TFSI V8 makes 420 horsepower and 405 lb-ft, swapping a modest drop in horsepower (from 429) for a bump in torque (from 398) over the outgoing V10. The sole transmission for the S6 is a 7-speed S-tronic dual-clutch unit feeding power to each corner via quattro all-wheel-drive. It’s a potent combination, allowing a 4.5-second bolt to 60 mph from a dead stop.
While the 4400-pound S6 can keep up with genuine sports cars in the sprint, it’s also quite docile to drive in real-world traffic. Unlike its V10 predecessor, peak torque can be summoned with as little as 1400 rpm on the tachometer. You don’t have to drive this one like an animal to dip into its performance potential.
Power delivery is exceptionally linear, feeling much more like a supercharged engine than one boosted by turbos. Missing is that wallop of out-of-nowhere torque that often accompanies high-strung V8s when the boost lights up. Instead, it has strength from down low and just keeps making more as the tach winds up. This engine is a distance runner more than a sprinter, eager to soak up long stretches of Autobahn at triple-digit speeds without breaking a sweat.
Cruising at a more relaxed pace allows the S6 to take advantage of its cylinder-deactivation feature. In steady-state driving where its only job is to maintain momentum, the engine seamlessly shuts down four of its cylinders, effectively becoming a naturally aspirated 2.0-liter miser. This works in conjunction with active engine mounts that counteract the resulting arrhythmia and an active noise cancelling system that tunes out unpleasant frequencies in the cabin. Automatic start-stop is also standard, and this whole collection of e